When Michele MacNeill’s 6-year-old child found her unresponsive in her bathtub, her daughters Alexis Somers and Rachel MacNeill immediately suspected that their father, Martin MacNeill, had killed her. It took authorities five years to charge Martin, a wealthy doctor and father of eight, with Michele’s murder. This update features new interviews with Alexis and Rachel, children of Michele and Martin; Doug Witney and Jeff Robinson, retired investigators who worked on both the identity fraud and murder cases; Chad Grunander, a prosecutor on the murder case; and crime writer Shanna Hogan, who wrote the book “The Stranger She Loved,” based on the story. “20/20” also includes interviews with Linda Cluff, Michele’s sister; Gypsy, Martin’s former mistress; Julie Willis, Gypsy’s sister; Doug and Kristi Daniels, the MacNeills’ neighbors who were on the scene after Michele’s death; Jill Harper, Michele’s niece; and Sergeant Josh Motsinger, one of the first police officers on the scene.